This Qantas 767-338 seat map page has a link for each of the variants in their fleet:
http://www.qantas.com.au/travel/airl...-763/global/en
Generally row 29 is windowless, and sometimes rows 24 and 30 on some variants are also windowless. Behind the wing there are no 'windowless window' seats if you want to be sure of getting a window.